US3727141A - Trigger circuit for a bistable multivibrator - Google Patents

Trigger circuit for a bistable multivibrator Download PDF

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Publication number
US3727141A
US3727141A US00197388A US3727141DA US3727141A US 3727141 A US3727141 A US 3727141A US 00197388 A US00197388 A US 00197388A US 3727141D A US3727141D A US 3727141DA US 3727141 A US3727141 A US 3727141A
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United States
Prior art keywords
charging circuit
circuit
electrical
output terminal
capacitor
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Expired - Lifetime
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US00197388A
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English (en)
Inventor
J Finlay
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Unisys Corp
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Burroughs Corp
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Assigned to BURROUGHS CORPORATION reassignment BURROUGHS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). DELAWARE EFFECTIVE MAY 30, 1982. Assignors: BURROUGHS CORPORATION A CORP OF MI (MERGED INTO), BURROUGHS DELAWARE INCORPORATED A DE CORP. (CHANGED TO)
Assigned to UNISYS CORPORATION reassignment UNISYS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). Assignors: BURROUGHS CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K5/00—Manipulating of pulses not covered by one of the other main groups of this subclass
    • H03K5/125—Discriminating pulses
    • H03K5/1252—Suppression or limitation of noise or interference
    • H03K5/1254—Suppression or limitation of noise or interference specially adapted for pulses generated by closure of switches, i.e. anti-bouncing devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/26—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback
    • H03K3/28—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback
    • H03K3/281—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator
    • H03K3/284—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of bipolar transistors with internal or external positive feedback using means other than a transformer for feedback using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator monostable

Definitions

  • ABSIRACT A set-reset trigger circuit for a bistable multivibrator is Apr. 3, Great Bfltam p o ided in a pair of electrical charging circuits are manually coupleable across a source of electric [52] US. Cl ..328/60, 307/247 A, 307/291, pow-er in a mutually reverse order with respect to their 7 328/196 328/206 individual elements to immediately thereby produce a [51] Ill. Cl.
  • the first device has provision for manually setting a bistable multivibrator to only one of two possible states or for manually ensuring that the multivibrator is already in a desired state. Additional circuitry must be employed to manually transfer the multivibrator to the opposite state.
  • the second device has provision for manually setting the multivibrator to either one of two possible states and requires a duplication of manually actuatable control switches and their associated circuitry.
  • the third device provides for manually transferring the multivibrator to the state opposite that to which it has initially been set. Additional circuitry is required to determine the initial setting.
  • Prior art also discloses manually actuatable trigger devices which internally generate spurious electrical pulses which, in extreme cases, might be erroneously interpreted by associated circuitry as set or reset pulses. Another problem common to devices disclosed by prior art are the effects of spurious electrical pulses generated by switch contact bounce.
  • the invention resides in the provision of a set-reset trigger circuit for manually setting a bistable multivibrator to a desired state and automatically resetting it after a predetermined period.
  • Yet another object of the invention is to provide a circuit wherein switch contact bounce is relatively unimportant.
  • Another object of the invention is to provide a circuit having all of the above-described advantages and which is additionally capable of setting a multivibrator to one state only.
  • An important aspect of the invention is the use of two parallel-connected, electrical charging circuits, each comprising a resistor and a capacitor so'disposed in series that the resistor of one and the capacitor of the other are respectively coupleable to a source of electrical power by a manually actuatable control switch.
  • Another important aspect of the invention is that the elements of the circuit are kept at ground potential to 'minimize spurious noise generation during the time the control switch remains unactuated.
  • FIG. 1 is an electrical schematic representation of a set-reset trigger circuit for a bistable multivibrator embodying features of the invention
  • FIG. 2 is a graphic representation of voltage plotted as a function of time as would appear at a point in the circuit shown by FIG. 1 upon actuation of the circuit;
  • FIG. 3 is a graphic representation of voltage plotted as a function of time as would appear at another point in the circuit shown by FIG. 1 upon actuation of the cir cuit;
  • FIG. 4 is an electrical schematic representation of the circuit of FIG. 1 shown operatively coupled in a typical manner to a bistable multivibrator;
  • FIG. 5 is an electrical schematic representation of a slightly modified embodiment of the circuit shown by FIG. 1.
  • the set-reset trigger circuit shown by FIG. 1 is normally connected to a source of electrical power (not shown) at the points 10 and 12, with the point 12 preferably being at ground potential. Until the control member or switch 14 is actuated, all of the components of the circuits will also be at ground potential.
  • the switch When the switch is first closed,'the first capacitor 16 will offer a very low impedance to the current flowing through the first electrical charging circuit generally indicated at 18; and the source voltage will effectively appear across the first resistor 20.
  • the voltage at the first output terminal 22, with respect to ground will, at this time, also effectively equal the source voltage.
  • FIG. 2 is a graphic representation of the decline of this voltage with respect to capacitor charging time. The shape of the curve shown is a function of the valuesof resistance and capacitance in the first charging circuit generally indicated at 18.
  • the source voltage will also be applied across the second electrical charging circuit generally indicated at 24 since it is connected in parallel to the first electrical charging circuit generally indicated at 18. It may be noted from FIG. 1 that the second resistor 26 is connected to the switch 14 and the second capacitor 28 to ground in the second charging circuit as opposed to the reverse order for the connection of the first capacitor 16 and first resistor 20 in the first charging circuit.
  • the second capacitor When the switch 14 is first closed, the second capacitor will offer a very low impedance to the current flowing through the second charging circuit; and the source voltage will effectively appear across the second resistor 26.
  • the second output terminal 30 will, at this time, effectively be at ground potential. As the second capacitor charges, however, its impedance to the current flow through the second charging circuit increases.
  • FIG. 3 is a graphic representation of the increase of this voltage with respect to capacitor charging time, the shape of this curve being a function of the values of resistance and capacitance in the second charging circuit generally indicated at 24.
  • the set-reset trigger circuit may be connected as shown by FIG. 4 to a bistable multivibrator or flip flop 34.
  • the first output terminal 22 would be connected to the set input of the flip flop through a first isolating diode 36, and the second output terminal 30 would be connected to the reset input of the flip flop through a second isolating diode 38.
  • a pulse initially equal to the source voltage would appear at the firstoutput terminal, thereby'setting the flip flop.
  • a pulse of sufficient magnitude to reset the flip flop would appear at the second output terminal.
  • the set-reset trigger circuit shown by FIG. 5 is essentially the same circuit as heretofore described; but the addition of a second control member or switch 40 and a unidirectional electrical current conducting member or diode 42 provides an option of producing a set pulse followed by a reset pulse or of producing a set pulse alone.
  • this trigger circuit when the switch 14 is closed a pulse similar to that represented by FIG. 2 will appear at the first output terminal 22, this being followed after a predetermined period by a pulse similar to that represented by FIG. 3 appearing at the second output terminal 30. If the trigger circuit were connected to a flip flop in a manner similar to that depicted by FIG. 4, actuating the switch 14 would have the effect of setting and subsequently resetting the flip flop.
  • a set-reset trigger circuit for a bistable multivibrator comprising:
  • a second electrical charging circuit operatively coupled in parallel to said first charging circuit and having a second output terminal
  • control member operatively coupled in series with i said first and said second charging circuits and with said resistance circuit and actuatable for operatively coupling a source of electrical power across said circuits, thereby producing an immediate set pulse at the first output terminal of said first charging circuit and a subsequent reset pulse at the second output terminal of said second charging circuit.
  • a setreset trigger circuit for a bistable multivibrator comprising:
  • a first control member operatively coupled in series with said second charging circuit and with said first charging circuit and said resistance circuit by said unidirectional current conducting member and actuatable for operatively coupling a source of electrical power across said circuits, thereby producing an immediate'set pulse at the first output terminal of said first charging circuit and a subsequent reset pulse at the second output terminal of said second charging circuit;
  • a second control member operatively coupled in series with said first charging circuit and said resistance circuit and actuatable for operatively coupling a source of electrical power across said circuits, said second charging circuit being electrically isolated by said unidirectional current conducting member, thereby producing an immediate set pulse at the first output terminal of said first charging circuit with no subsequent reset pulse being produced at the second output terminal of said second charging circuit.
  • a set-reset trigger circuit for a bistable multivibrator comprising:
  • a first electrical charging circuit comprised of a first capacitor coupled in series with a first resistor

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electronic Switches (AREA)
US00197388A 1971-04-03 1971-11-10 Trigger circuit for a bistable multivibrator Expired - Lifetime US3727141A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB863271 1971-04-03

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US (1) US3727141A (enrdf_load_stackoverflow)
GB (1) GB1305696A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3894247A (en) * 1973-12-26 1975-07-08 Rockwell International Corp Circuit for initalizing logic following power turn on
US3943381A (en) * 1972-09-07 1976-03-09 Canon Kabushiki Kaisha Pulse generating apparatus having a chattering pulse elimination circuit
US4015142A (en) * 1974-07-22 1977-03-29 Seiko Koki Kabushiki Kaisha Electric timing circuitry with means to compensate for switch chatter

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4181919A (en) * 1978-03-28 1980-01-01 Ncr Corporation Adaptive synchronizing circuit for decoding phase-encoded data

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2909675A (en) * 1955-05-10 1959-10-20 Bell Telephone Labor Inc Bistable frequency divider
US3105939A (en) * 1959-09-15 1963-10-01 Marconi Co Canada Precision time delay generator
US3264496A (en) * 1963-10-17 1966-08-02 Bosch Gmbh Robert Rotational speed responsive electronic switch

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2909675A (en) * 1955-05-10 1959-10-20 Bell Telephone Labor Inc Bistable frequency divider
US3105939A (en) * 1959-09-15 1963-10-01 Marconi Co Canada Precision time delay generator
US3264496A (en) * 1963-10-17 1966-08-02 Bosch Gmbh Robert Rotational speed responsive electronic switch

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3943381A (en) * 1972-09-07 1976-03-09 Canon Kabushiki Kaisha Pulse generating apparatus having a chattering pulse elimination circuit
US3894247A (en) * 1973-12-26 1975-07-08 Rockwell International Corp Circuit for initalizing logic following power turn on
US4015142A (en) * 1974-07-22 1977-03-29 Seiko Koki Kabushiki Kaisha Electric timing circuitry with means to compensate for switch chatter

Also Published As

Publication number Publication date
GB1305696A (enrdf_load_stackoverflow) 1973-02-07

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Owner name: BURROUGHS CORPORATION

Free format text: MERGER;ASSIGNORS:BURROUGHS CORPORATION A CORP OF MI (MERGED INTO);BURROUGHS DELAWARE INCORPORATEDA DE CORP. (CHANGED TO);REEL/FRAME:004312/0324

Effective date: 19840530

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Owner name: UNISYS CORPORATION, PENNSYLVANIA

Free format text: MERGER;ASSIGNOR:BURROUGHS CORPORATION;REEL/FRAME:005012/0501

Effective date: 19880509